Screw-propeller



UNITED STATES PATENT OFFICE.

DAVID GREENE-HASKINS, 0F CAMBRIDGE, MASSACHUSETTS.

scREw-PROPELLER.

SPECIFICATION forming part of Letters Patent No. 224,289, dated February 1Q, 1880.

Application fue@ June 12, 1879.

To all 'whom it may concern:

f Be it known that I, DAVID GREENE Has- KINS, o f Cambridge, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Screw-Propellers, of which the following is a specication. v

The object of my invention is to provide a means for increasing the-power and effective-` ness of screw-propellers, especially in preventing the loss from slip.

My invention consists inthe employment, instead of single blades, upon the propellershaft, of groupsof blades, each blade of the group being arrangedone nearly in front of the other, and increasing progressively in length and width from the front blade, which is the smallest, to the rearmost blade, which is thelargest. The blades in each group are so arranged relatively that as the propeller rotates the advancing edge of the rearmost or largest blade shall eut the Water first and be followed successively by each of the `other blades of the group to the foremost or smallest blade, which cuts the water last.

Referring to the drawings, Figure l represents a front view of a propeller embodying my invention. Fig. 2 isa side or end view of the same. y

A B U represent a group of three blades, there being represented three such groups upon the shaft. A A A are th 1earmost and largest blades, which may be cas with or form a part of a central bearing, F, journaled upon the shaft D.

In front of the blades A are placed the blades B B B, which are of less length and width than the blades A, as shown, and having their radial advancing edges at an angle with those of the blades A.

In front of' the blades B are arranged the blades C C C, of less length and width than the blades B, and having their radial advancin g edges'at an angle with those ot' the blades B.

The rotation of the blades is in the direction indicated by the arrow, so that the blades A will cut the water first and be followed sueeessively by thel blades B and C.

By this construction and arrangement of the blades the water, as the vessel advances, is caught by the projecting portions of the several blades and turned into the spaces between the same, where the force and reaction of the water serve to Y impart the greatest efficiency to the propeller and prevent slip.

By making the blades of the several groups l of unequal length, increasing from the front Lto the rearmost blade, that portion of each blade where its leverage to turn the propeller is greatestis exposed to the direct action of the water, which also, as the wheel advances,

The blades B O may be attached to a blade, A, representing that of any propeller, by means of rivets or otherwise, at a point near its connection with the shaft.

I have described a propeller as composed of three groups ofiolades; but two groups may be sufficient, and more than three may be used.

What I claim as my invention is- 1. A propeller composed of two or more groups of blades, each blade of each group dili'ering in size, and each diminishing in size .from the rear to the front blade, substantially as specied.

2. A propeller composed of groups of blades of unequal length and width, in which the blades of each group areso arranged that the advancing edges of the several blades of each group shall strike the Water in-suceession, the

edges of the rearmost blades cutting the water first and those of the front blades cutting the Water last, substantially as set forth.

In testimony whereof I have signed my name 'to this specification in the presence of two subscribing witnesses.

DAVID GREENE Witnesses J os. H. ADAMS,

J. OPPENHEDVLER.

Erasmus. n 

